Is this the beginnings of a raycaster?

Dangit, I wish I could do that

To remove the fisheye effect, you will want to calculate the distance of the walls not from the camera position, but from a line that goes through the camera position and is perpendicular to the view direction.

All you have to do to remove the fishbowl effect is multiply by cos(θ) where θ is the angle from dead-ahead (see http://www.permadi.com/tutorial/raycast/rayc8.html for an explanation).

Nice job—raycasting is always fun

I can't really give a good description myself, but the graphics kinda look like dis:


http://en.wikipedia.org/wiki/Ray_casting

What is raycasting?

It means projecting a ray into an environment to render it. In this case, rays are cast into a 2D grid of tiles, one for ever column of the screen, and the distance the rays travel is used to calculate the vertical height of the wall rendered.

Some time ago, I made my own raycaster, however I halted the project... I need to finish it some day

Yours looks awesome so far
Looking at your code, I realized that it is quite slow. You only draw 1/4 segments of the screen, and it is running at 15 Mhz. I'm not an expert at raycasting, but I think you need to restructure parts of the code to really optimize it. Still, here are some minor optimization tricks you could use (but I don't think they really matter that much):

Pt-Off(0,,Pic0,L3)
If pxl-Test(V/8,W/8,L3)Using a sprite is a cool idea to store the map, but the pixel-test function is incredible slow (and you're doing that a lot each frame!). Try directly accessing the data, e.g. in an 2d array/matrix etc.



The next optimization helps almost everywhere:
If size doesn't matter, use a bunch of /2 instead of dividing by a power of 2. For example:
A/2/2/2 is faster than /8
This trick works due to the fact that /2 is replaced by a shift operation, whereas every other division calls a routine to divide (which is kinda slow)

√(((abs(X-V)²)+(abs(Y-W)²)))→GHere you can leave out the abs(), because squaring gets rid of the sign. You don't even need the first parenthesis. So:
√(X-V²+(Y-W)²)→G


If r1<64 or (r1>192)Almost in every case you can substitute a logic "or" by an addition.
If r1<64 + (r1>192)


I think the slowest part of your code is this, I don't know how to optimize this though, because I don't understand what you want to do with that.
Lbl TH
abs(Y-W)*128//sin(r1-r2)*cos(r1-r2)//128→U
r1<128?U+X→V,X-U→V
Return

Lbl TV
abs(V-X)*128//cos(r1)*sin(r1)//128→U
ReturnThis code looks slow because of signed division and trigonometry. These functions are also called a lot each frame!



Also, if you need a function only once in the code, you can type it inline where you need it to save some bytes and cycles without the call.
If you want to keep readability, you can include them in another program.
Also, what helps reading the code is the C++ style function calling syntax:
Function(arguments) instead of sub(Function,arguments)
For example:
sub(TH,r1,128) becomes TH(r1,128)


I guess that's my part for now, maybe I take a closer look on it later. I hope it helps you a bit and good luck with your project.